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Abdulla MH, Sattar MA, Abdullah NA, Khan MAH, Anand Swarup KRL, Johns EJ. The effect of losartan and carvedilol on vasopressor responses to adrenergic agonists and angiotensin II in the systemic circulation of Sprague Dawley rats. ACTA ACUST UNITED AC 2010; 31:13-20. [PMID: 21166975 DOI: 10.1111/j.1474-8673.2010.00461.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1 Interaction between renin-angiotensin (RAS) and sympathetic nervous systems (SNS) was investigated by examining the effect of cumulative blockade of angiotensin II (Ang II) and adrenergic receptors in normal Sprague Dawley rats. 2 Rats were treated with losartan (10 mg/kg), carvedilol (5 mg/kg), or losartan plus carvedilol (10+5 mg/kg) orally for 7 days. On day 8, the animals were anaesthetized with pentobarbitone and prepared for systemic haemodynamic study. Dose-response relationships for the elevation of mean arterial pressure or change in heart rate (HR) in response to intravenous injections of noradrenaline (NA), phenylephrine (PE), methoxamine (ME) and Ang II were determined. 3 Losartan or the combination of losartan with carvedilol blunted vasopressor responses to ME and Ang II. Dose-response relationships for agonist action on HR were significantly inhibited by all treatments except for the combination of losartan and carvedilol on the decrease in HR induced by PE. Carvedilol decreased vasopressor responses to NA, PE and Ang II, and HR responses to NA, ME and Ang II. Combination treatment produced similar effects to losartan on the vasopressor and HR responses but had a greater effect on vasopressor responses to ME and Ang II, and on HR responses to NA and Ang II than carvedilol alone. 4 It is concluded that peripheral vasoconstriction induced by Ang II is partly mediated by adrenergic action and that the vasopressor responses to adrenergic agonists depend on an intact RAS. These observations suggest an interactive relationship between RAS and SNS in determining systemic haemodynamic responses in 'normal' rats.
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Salman IM, Sattar MA, Ameer OZ, Abdullah NA, Yam MF, Salman HM, Khan MHA, Johns EJ. Role of norepinephrine & angiotensin II in the neural control of renal sodium & water handling in spontaneously hypertensive rats. Indian J Med Res 2010; 131:786-792. [PMID: 20571167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Abstract
BACKGROUND & OBJECTIVES A wealth of information concerning the essential role of renal sympathetic nerve activity (RSNA) in the regulation of renal function and mean arterial blood pressure homeostasis has been established. However, many important parameters with which RSNA interacts are yet to be explicitly characterized. Therefore, the present study aimed to investigate the impact of acute renal denervation (ARD) on sodium and water excretory responses to intravenous (iv) infusions of either norepinephrine (NE) or angiotensin II (Ang II) in anaesthetized spontaneously hypertensive rats (SHR). METHODS Anaesthetized SHR were acutely denervated and a continuous iv infusion of NE (200 ng/min/ kg) or Ang II (50 ng/min/kg) was instigated for 1 h. Three 20-min urine clearances were subsequently collected to measure urine flow rate (UV) and absolute sodium excretion (U(Na)V). RESULTS Higher UV and U(Na)V (P<0.05) were observed in denervated control SHR as compared to innervated counterparts. The administration of NE or Ang II to innervated SHR produced lower UV and U(Na)V (P<0.05 vs. innervated control SHR). Lower diuresis/natriuresis response to ARD was observed in NE-treated SHR compared to denervated control SHR (P<0.05). Salt and water excretions in denervated NE-treated SHR, however, were significantly higher (P<0.05) relative to the excretion levels in control denervated SHR. Conversely, there was a higher (all P<0.05) diuresis/natriuresis response to ARD when Ang II was administered to SHR compared to denervated control or innervated Ang II-treated SHR. INTERPRETATION & CONCLUSIONS NE retains its characteristic antidiuretic/antinatriuretic action following ARD in SHR. Typical action of Ang II on salt and water excretions necessitates the presence of an intact renal innervation. Ang II is likely to facilitate the release of NE from renal sympathetic nerve terminals through a presynaptic site of action. Moreover, there is a lack of an immediate enhancement in the renal sensitivity to the actions of NE and Ang II following ARD in a rat model of essential hypertension.
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Salman IM, Sattar MA, Abdullah NA, Ameer OZ, Basri F, Hussain NM, Yam MF, Swarup KRLA, Rathore HA, Kazi RN, Hye Khan MA, Johns EJ. Role of renal sympathetic nervous system in the control of renal potassium handling. J Nephrol 2010; 23:291-296. [PMID: 20349424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2009] [Indexed: 05/29/2023]
Abstract
BACKGROUND It is well established that renal sympathetic nerves are primarily involved in renal sodium and water regulation. However, the relationship between renal sympathetic nerve activity (RSNA) and renal potassium handling is not extensively known. The present study was performed to investigate the role of the renal sympathetic nervous system in the regulation of tubular potassium reabsorption and secretion. METHODS Male Sprague Dawley (SD) rats (each group, n=6) were fasted overnight, anesthetized with pentobarbital sodium (60 mg/kg intraperitoneal), denervated by application of phenol to the left renal artery and maintained on an intravenous infusion of saline for 2 hours. During this period, 6 urine and plasma samples were collected at 20-minute intervals to study kidney function parameters. RESULTS In denervated rats, there were significantly higher (all p<0.05 vs. innervated control) urine flow rate (UFR), glomerular filtration rate (GFR), absolute sodium excretion (U(Na)V), fractional sodium excretion (FE(N)a), absolute potassium excretion (U(K)V), fractional potassium excretion (FE(K)) and urinary sodium to urinary potassium ratio (U(Na)/U(K)). No appreciable differences were seen in the mean arterial pressure (MAP) and plasma sodium (P(Na)) between denervated and innervated SD rats. However, plasma potassium (P(K)) levels were significantly lower (p<0.05) in denervated rats as compared with innervated counterparts. CONCLUSIONS There is a possible involvement of renal nerves in the regulation of renal potassium handling. This effect is largely attributable to a direct action of renal sympathetic nerves on the renal tubular segments.
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Salman IM, Ameer OZ, Sattar MA, Abdullah NA, Yam MF, Najim HS, Abdul Hye Khan M, Johns EJ. Role of the renal sympathetic nervous system in mediating renal ischaemic injury-induced reductions in renal haemodynamic and excretory functions. Pathology 2010; 42:259-66. [DOI: 10.3109/00313021003631304] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abdulla MH, Sattar MA, Abdullah NA, Khan MAH, Anand Swarup KRL, Rathore HA, Ibraheem ZO, Johns EJ. EFFECT OF CARVEDILOL AND LOSARTAN ON RENAL RESPONSES TO ANG II AND ADRENERGIC AGONISTS IN FRUCTOSE‐FED RAT. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.605.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Salman IM, Ameer OZ, Sattar MA, Abdullah NA, Yam MF, Khan MAH, Johns EJ. Sympathetic nervous system interacts with renin‐angiotensin system to control renal sodium and water handling in SHR rat. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.1050.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Salman IM, Sattar MA, Abdullah NA, Ameer OZ, Yam MF, Kaur G, Khan MAH, Johns EJ. Renal Ischemic Injury Affects Renal Hemodynamics and Excretory Functions in Sprague Dawley Rats: Involvement of Renal Sympathetic Tone. Ren Fail 2010; 32:96-102. [DOI: 10.3109/08860220903389196] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Salman IM, Sattar MA, Abdullah NA, Ameer OZ, Hussain FBNM, Hye Khan MA, Yam MF, Rathore KRLASHA, Kazi RN, Salman HM, Johns EJ. Renal functional & haemodynamic changes following acute unilateral renal denervation in Sprague Dawley rats. Indian J Med Res 2010; 131:76-82. [PMID: 20167977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND & OBJECTIVES Regulation of renal function and haemodynamics are under a direct control from the renal sympathetic nerves and renal denervation produces overt diuresis and natriuresis in several mammalian species. However, the inter-related series of changes in renal function and haemodynamics following acute renal denervation (ARD) is not fully understood. Thus, we aimed to investigate and relate the changes in renal function and haemodynamics following acute unilateral renal denervation in anaesthetized Sprague Dawley (SD) rats. METHODS Male SD rats were fasted overnight, anaesthetized with sodium pentobarbitone (60 mg/kg ip), denervated by application of phenol to the left renal artery and maintained on an intravenous (iv) infusion of isotonic saline for 2 h. Throughout this period, six urine and plasma samples were taken at 20-min intervals to study kidney function parameters. In a different set of experiments, renal nerve stimulation (RNS) was carried out to characterize the changes in renal vasoconstrictor responses following ARD. RESULTS Denervated animals showed significantly (P<0.05 vs. control innervated rats) higher urine flow rate (UFR), absolute sodium excretion (UNaV), fractional sodium excretion (FENa) and glomerular filtration rate (GFR). The renal vasoconstrictor responses to RNS were significantly (P<0.05) lower in denervated rats as compared to the innervated counterparts. However, no appreciable differences were seen in the mean arterial pressure (MAP), plasma sodium (PNa), basal renal blood flow (RBF) and basal renal vascular resistance (RVR) in both innervated and denervated SD rats. INTERPRETATION & CONCLUSIONS Natriuresis, diuresis, enhanced GFR and impaired vasoconstriction in response to RNS are typical and instant responses to ARD in SD rats. Renal sympathetic nerves serve more important role in salt and water conservation than in dynamic autoregulation of RBF under normal sympathetic tone; yet, their effects on renal haemodynamics become more evident in the presence of augmented renal sympathetic nerve activity (RSNA).
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Rathore HA, Munavvar AS, Abdullah NA, Khan AH, Fathihah B, NurJannah MH, Raisa NA, Anand Swarup KRL, Abdullah MH, Salman IM, Johns EJ. Interaction between renin-angiotensin and sympathetic nervous systems in a rat model of pressure overload cardiac hypertrophy. ACTA ACUST UNITED AC 2009; 29:171-80. [PMID: 19740088 DOI: 10.1111/j.1474-8665.2009.00445.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
1 A raised cardiac workload activates neurohormones which will increase muscle mass and shift contractility to the right along the Frank-Starling curve. 2 This study examined the interaction between the SNS and RAS in contributing to vascular responsiveness following the development of cardiac hypertrophy due to aortic banding. 3 Sprague Dawley rats (180-200 g) were assigned to one of six groups; Normal, Sham-operated, Aortic Banded (AB), Aortic Banded treated with losartan (ABLOS), Aortic Banded treated with 6-hydroxydopamine (ABSYMP) and Aortic banded treated with both losartan and 6-hydroxydopamine (ABSYMPLOS). A constricting band was placed around the supra renal aorta on day zero with drug treatment from day 37 to day 44. Vasopressor responses to noradrenaline, phenylephrine, methoxamine and angiotensin II were measured on day 45. 4 The magnitudes of the MAP responses to all vasoactive agents, expressed as percentage changes, were similar in Normal and Sham groups, but reduced in the AB group. ABLOS group showed attenuated response to ANGII whereas all responses were enhanced in the ABSYM group. 5 A positive interaction between the two systems was observed with alpha(1A)-adrenoceptors identified as a major component of SNS and AT(1) receptors of RAS to induce vasopressor effects.
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Kazi RN, Munavvar AS, Abdullah NA, Khan AH, Johns EJ. Influence of high dietary sodium intake on the functional subtypes of alpha-adrenoceptors in the renal cortical vasculature of Wistar-Kyoto rats. ACTA ACUST UNITED AC 2009; 29:25-31. [PMID: 19302553 DOI: 10.1111/j.1474-8673.2009.00428.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1 Increased renal vascular resistance is one renal functional abnormality that contributes to hypertension, and alpha(1)-adrenoceptors play a pivotal role in modulating this renal vascular resistance. This study investigates the functional contribution of alpha(1)-adrenoceptor subtypes in the renal cortical vasculature of Wistar-Kyoto rats on a normal sodium diet (WKYNNa) compared with those given saline to drink for 6 weeks (WKYHNa). 2 The renal cortical vascular responses to the adrenergic agonists noradrenaline (NA), methoxamine (ME) and phenylephrine (PE) were measured in WKYHNa and WKYNNa rats either in the absence (the control phase) or presence of chloroethylclonidine (CEC), an alpha(1B)-adrenoceptor antagonist, 5-methylurapidil (5-MeU), an alpha(1A) antagonist, or BMY7378, an alpha(1D) antagonist. 3 Results showed a greater renal cortical vascular sensitivity to NA, PE and ME in the WKYHNa compared with WKYNNa rats (P < 0.05). Moreover, 5-MeU and BMY7378 attenuated adrenergically induced renal cortical vasoconstriction in WKYHNa and WKYNNa rats; this response was largely blunted in CEC-treated WKYHNa rats (all P < 0.05) but not in CEC-treated WKYNNa rats. 4 The data suggest that irrespective of dietary sodium content, in Wistar-Kyoto rats alpha(1A)- and alpha(1D)-subtypes are the major alpha(1)-adrenoceptors in renal cortical vasculature; however, there appears to be a functional involvement of alpha(1B)-adrenoceptors in the WKYHNa rats.
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Khan AH, Sattar MA, Abdullah NA, Johns EJ. EFFECT OF CALCIUM CHANNEL BLOCKADE ON ADRENERGICALLY INDUCED RENAL VASOCONSTRICTION IN RAT MODELS OF RENAL IMPAIRMENT. Clin Exp Pharmacol Physiol 2009; 36:501-8. [DOI: 10.1111/j.1440-1681.2008.05098.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Johns EJ, Abdulla MH, Sattar MA, Abdullah NA, Khan AH. The effect acute unilateral renal denervation on renal vasoconstrictions in spontaneously hypertensive rats (SHR) treated with a combination of carvedilol and losartan. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.1017.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Khan MAH, Sattar MA, Abdullah NA, Majid DSA, Johns EJ. Influence of experimental early diabetic nephropathy on the functional subtypes of renal α1‐adrenoceptor in spontaneously hypertensive rats (SHR). FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.971.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abdulla MH, Sattar MA, Khan MAH, Abdullah NA, Johns EJ. Influence of sympathetic and AT-receptor blockade on angiotensin II and adrenergic agonist-induced renal vasoconstrictions in spontaneously hypertensive rats. Acta Physiol (Oxf) 2009; 195:397-404. [PMID: 19183357 DOI: 10.1111/j.1748-1716.2008.01895.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIM This study investigated the influence of angiotensin II (Ang II) receptor and adrenergic blockade on the renal vasoconstrictions caused by Ang II and adrenergic agonists in spontaneously hypertensive rats (SHR). METHODS Forty-eight SHR were subjected to 7 days of losartan (10 mg kg(-1) day(-1) p.o.), carvedilol (5 mg kg(-1) day(-1) p.o.) or losartan + carvedilol (10 mg kg(-1) day(-1) + 5 mg kg(-1) day(-1) p.o.). On day 8, the rats were anaesthetized and renal vasoconstrictor experiments performed. One group of rats underwent acute unilateral renal denervation. RESULTS There were significant (P < 0.05) reductions in the renal vasoconstrictor responses to noradrenaline, phenylephrine, methoxamine and Ang II after losartan and carvedilol treatments compared with that in untreated rats (all P < 0.05). However, in renally denervated SHR treated with carvedilol, the vasoconstrictor responses to all the vasoactive agents were enhanced compared with those in SHR with intact renal nerves treated with carvedilol. Intact SHR given both losartan and carvedilol showed greater renal vasoconstrictor responses to the vasoactive agents than when given either losartan or carvedilol alone (all P < 0.05). CONCLUSION Carvedilol reduced the vasoconstrictor response to Ang II and all the adrenergic agonists in the presence of the renal nerves, but, following the removal of renal sympathetic activity, carvedilol enhanced the sensitivity of both renal alpha(1)-adrenoceptors and AT(1) receptors to the vasoactive agents. Co-treatment with losartan and carvedilol reduced the renal vasoconstrictor responses to exogenously administered vasoactive agents but to a lesser extent than losartan or carvedilol alone. The results obtained demonstrate an interaction between Ang II receptors and adrenergic neurotransmission in the SHR.
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Lazahari MIA, Sattar MA, Abdullah NA, Khan MAH, Johns EJ. Clonidine and a novel clonidine analog AL-12 cause sympathoinhibition in spontaneously hypertensive and diabetic spontaneously hypertensive rats. METHODS AND FINDINGS IN EXPERIMENTAL AND CLINICAL PHARMACOLOGY 2008; 30:193-9. [PMID: 18597003 DOI: 10.1358/mf.2008.30.3.1166221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
This study examined the sympathoinhibitory effects of clonidine and a novel clonidine analog, AL-12, in rat models of genetic hypertension and a combined state of genetic hypertension and diabetes. Rats in the treatment groups were given either clonidine or AL-12 while the respective control groups received either saline or Tween 80 for 6 days. Physiological data were collected during this period, which was followed by acute studies on day 7 when bolus administrations (i.v.) of graded doses of noradrenaline, phenylephrine and methoxamine were carried out. It was observed that in AL-12-treated nondiabetic spontaneously hypertensive rats (SHR), the pressure responses to all adrenergic agonists were greater (p < 0.05) in the treated group, while in the diabetic SHR rats a larger pressure response was observed only to noradrenaline (p < 0.05). In nondiabetic SHR rats treated with clonidine, a greater (p < 0.05) pressure response was observed only in the case of phenylephrine. In the diabetic SHR rats treated with clonidine, the pressure responses to the adrenergic agonists were similar (p > 0.05) in the treated and its control animals except that methoxamine caused a greater (p < 0.05) pressure response in the control group. The data obtained suggest that clonidine and AL-12 act possibly via vascular alpha1 and alpha2 adrenoceptors present at both pre- and postsynaptic locations.
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Khan AH, Sattar MA, Abdullah NA, Johns EJ. Influence of cisplatin-induced renal failure on the α1-adrenoceptor subtype causing vasoconstriction in the kidney of the rat. Eur J Pharmacol 2007; 569:110-8. [PMID: 17559832 DOI: 10.1016/j.ejphar.2007.04.063] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 04/17/2007] [Accepted: 04/20/2007] [Indexed: 10/23/2022]
Abstract
This study investigated whether the alpha(1)-adrenoceptor subtype(s) mediating the vasoconstrictor actions of the renal sympathetic nerves were altered in rats with cisplatin-induced renal failure. Male Wistar Kyoto rats were used and half received cisplatin (5 mg/kg i.p.) to induce renal failure and were taken for study 7 days later. The renal blood flow reductions caused by electrical renal nerve stimulation and close intra-renal administration of noradrenaline, phenylephrine and methoxamine were determined before and after amlodopine (AMP), 5-methylurapidil (MeU), chloroethylclonidine (CEC) or BMY 7378. Water intake and creatinine clearance were decreased (P<0.05) by 40-50% while fractional excretion of sodium was increased two-fold in the cisplatin treated rats. Mean arterial pressure was higher, 110+/-2 versus 102+/-3 mmHg and renal blood flow was lower, 10.7+/-0.9 versus 18.9+/-0.1 ml/min/kg in the renal failure rats (both P<0.05). AMP, MeU and BMY 7378 decreased (all P<0.05) the adrenergically induced renal vasoconstrictor responses in the renal failure groups by 30 to 50% and in normal rats by 20 to 40%. In the presence of CEC, renal nerve stimulation and noradrenaline and methoxamine induced renal vasoconstrictor responses were enhanced (all P<0.05) in the renal failure but not in the normal rats. These data showed that alpha(1A)- and alpha(1D)-adrenoceptors were the major subtypes in mediating adrenergically induced renal vasoconstriction but there was no substantial shift in subtype in renal failure. The contribution of alpha(1B)-adrenoceptor subtypes either pre- or post-synaptic appeared to be raised in the renal failure rats.
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Abdullah NA, Pearce MS, Parker L, Wilkinson JR, McNally RJQ. Evidence of an environmental contribution to the aetiology of cryptorchidism and hypospadias? Eur J Epidemiol 2007; 22:615-20. [PMID: 17636413 DOI: 10.1007/s10654-007-9160-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Accepted: 01/26/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Evidence suggests that there is geographical variation in the birth prevalence of both cryptorchidism and hypospadias. The aim was to determine if there is evidence of spatial heterogeneity in the prevalence of these conditions and to test the hypothesis that environmental factors may contribute to aetiology. METHODS A population-based dataset of cryptorchidism and hypospadias cases was constructed from the hospital episodes statistics that covered the Northern Region of England and assigned to a small area based on the residential address at time of admission. Expected numbers of cases for each small area were computed. The ratio of observed to expected cases was determined for each small area and analysed with respect to both geographical heterogeneity and small area level socio-economic deprivation. The Potthoff-Whittinghill method was used to determine if there was localized spatial clustering of cases. RESULTS There was statistically significant spatial clustering for cases of both cryptorchidism [estimated Extra-Poisson Variation (EPV) = 0.14; 95% CI, 0.03-0.25] and hypospadias (EPV = 0.17; 95% CI, 0.05-0.28). In addition, increased prevalence was associated with lower levels of deprivation for hypospadias (P = 0.06), but there was no such relationship for cryptorchidism (P = 0.61). CONCLUSIONS The finding of localized spatial heterogeneity in the prevalence of cryptorchidism and hypospadias is consistent with the involvement of a spatially varying environmental risk factor. The apparent social patterning of hypospadias is likely to reflect an association with lifestyle and other factors which underpin social variation in health. However, there also remains a possibility that these findings may be due to variability in ascertainment of cases.
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Abdullah NA, Pearce MS, Parker L, Wilkinson JR, Jaffray B, McNally RJQ. Birth prevalence of cryptorchidism and hypospadias in northern England, 1993-2000. Arch Dis Child 2007; 92:576-9. [PMID: 17142312 PMCID: PMC2083772 DOI: 10.1136/adc.2006.102913] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIM There is much debate as to whether the prevalence rates of cryptorchidism and hypospadias are increasing. To address this issue we investigated the birth prevalence of cryptorchidism and hypospadias in the northern region of England during the period 1993-2000. METHODS Cases of cryptorchidism and hypospadias were identified from northern region hospital episodes statistics (HES). Trends in birth prevalence, based on the number of male live births, were assessed using linear regression. RESULTS Prevalence was 7.6 per 1000 male live births for cryptorchidism and 3.1 per 1000 male live births for hypospadias. The orchidopexy rates for 0-4 year olds and 5-14 year olds were 1.8 and 0.8 per 1000 male population, respectively. The rates for hypospadias repair for 0-4 year olds and 5-14 year olds were 0.6 and 0.1 per 1000 male population, respectively. There was a statistically significant decreasing temporal trend for the corrective procedure in cryptorchidism of 0.1 per 1000 male population aged under 5 years per annum (95% confidence interval: -0.01 to -0.05, p<0.001), but no temporal change for the corrective procedure in hypospadias (p = 0.60). CONCLUSION HES data were of high quality for the study period. There was no significant change in the prevalence of surgically corrected hypospadias. However, there was an apparent decline in the prevalence of surgically corrected cryptorchidism that may reflect a decrease in the prevalence of the condition or may be due to a decrease in the rate of surgical intervention.
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McNally RJQ, Abdullah NA, Pearce MS, Parker L, Wilkinson JR. Space-Time Clustering of Cryptorchidism and Hypospadias. Epidemiology 2007; 18:183-4. [PMID: 17179765 DOI: 10.1097/01.ede.0000249528.93963.be] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Armenia A, Munavvar AS, Abdullah NA, Helmi A, Johns EJ. The contribution of adrenoceptor subtype(s) in the renal vasculature of diabetic spontaneously hypertensive rats. Br J Pharmacol 2004; 142:719-26. [PMID: 15172958 PMCID: PMC1575052 DOI: 10.1038/sj.bjp.0705842] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Diabetes and hypertension are both associated with an increased risk of renal disease and are associated with neuropathies, which can cause defective autonomic control of major organs including the kidney. This study aimed to examine the alpha(1)-adrenoceptor subtype(s) involved in mediating adrenergically induced renal vasoconstriction in a rat model of diabetes and hypertension. 2. Male spontaneously hypertensive rats (SHR), 220-280 g, were anaesthetized with sodium pentobarbitone 7-day poststreptozotocin (55 mg x kg(-1) i.p.) treatment. The reductions in renal blood flow (RBF) induced by increasing frequencies of electrical renal nerve stimulation (RNS), close intrarenal bolus doses of noradrenaline (NA), phenylephrine (PE) or methoxamine were determined before and after administration of nitrendipine (Nit), 5-methylurapidil (5-MeU), chloroethylclonidine (CEC) and BMY 7378. 3. In the nondiabetic SHR group, mean arterial pressure (MAP) was 146+/-6 mmHg, RBF was 28.0+/-1.4 ml x min(-1) x kg(-1) and blood glucose was 112.3+/-4.7 mg x dl(-1), and in the diabetic SHR Group, MAP was 144+/-3 mmHg, RBF 26.9+/-1.3 ml(-1) min x kg(-1) and blood glucose 316.2+/-10.5 mg x dl(-1). Nit, 5-MeU and BMY 7378 blunted all the adrenergically induced renal vasoconstrictor responses in SHR and diabetic SHR by 25-35% (all P<0.05), but in diabetic rats the responses induced by RNS and NA treated with 5-MeU were not changed. By contrast, during the administration of CEC, vasoconstrictor responses to all agonists were enhanced by 20-25% (all P<0.05) in both the SHR and diabetic SHR. 4. These findings suggest that alpha(1A) and alpha(1D)-adrenoceptor subtypes contribute in mediating the adrenergically induced constriction of the renal vasculature in both the SHR and diabetic SHR. There was also an indication of a greater contribution of presynaptic adrenoceptors, that is, alpha(1B)-, and/or alpha(2)-subtypes.
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MESH Headings
- Animals
- Blood Glucose/drug effects
- Blood Glucose/metabolism
- Clonidine/administration & dosage
- Clonidine/analogs & derivatives
- Clonidine/pharmacokinetics
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/physiopathology
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Electric Stimulation/methods
- Infusions, Intravenous
- Injections, Intraperitoneal
- Injections, Intravenous
- Kidney/blood supply
- Kidney/innervation
- Kidney/physiopathology
- Kidney Cortex/blood supply
- Kidney Cortex/drug effects
- Malaysia
- Male
- Methoxamine/administration & dosage
- Methoxamine/antagonists & inhibitors
- Methoxamine/pharmacokinetics
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiopathology
- Nitrendipine/administration & dosage
- Nitrendipine/pharmacokinetics
- Norepinephrine/administration & dosage
- Norepinephrine/pharmacokinetics
- Phenylephrine/administration & dosage
- Phenylephrine/antagonists & inhibitors
- Phenylephrine/pharmacokinetics
- Piperazines/administration & dosage
- Piperazines/pharmacokinetics
- Rats
- Rats, Inbred SHR
- Receptors, Adrenergic, alpha-1/classification
- Receptors, Adrenergic, alpha-1/drug effects
- Receptors, Adrenergic, alpha-1/physiology
- Streptozocin/administration & dosage
- Streptozocin/adverse effects
- Time Factors
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
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Abdullah NA, Sorour MH. Current perspectives and opportunities for international cooperation for development of polymer based drug delivery systems. PAKISTAN JOURNAL OF PHARMACEUTICAL SCIENCES 1997; 10:41-50. [PMID: 16414802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The present paper is devoted to: Analysis of significant endeavours directed to polymer base drug delivery systems, elucidating addressing priority problems and biopolymer development, significant R & D needs and priorities and the framework as well as the requirements for international networking in the area of drug delivery system. Such organized collaboration will enable promotion of knowledge among interested parties and cultures. Concerned pharmaceutical institutional and scientific associations e.g. International Pharmaceutical Federation FIP and American Association of Pharmaceutical Sciences AAPS should adopt and initiate planned activities for developing and activation of appropriate drug network encompassing active members from the academic, professional centres and drug industry. The proposed network should be established on a self-sustained basis.
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Yamada K, Chen S, Abdullah NA, Tanaka M, Ito Y, Inoue R. Electrophysiological characterization of a motilin agonist, GM611, on rabbit duodenal smooth muscle. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 271:G1003-16. [PMID: 8997244 DOI: 10.1152/ajpgi.1996.271.6.g1003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Effects of motilin and a newly synthesized erythromycin derivative, GM611, on membrane potential and currents of rabbit duodenal smooth muscle have been investigated by intracellular potential recording and whole cell patch-clamp technique and compared with results from contractile experiments. Motilin and GM611 (0.01-100 nM) dose dependently produced slowly sustained depolarizations (half-maximal effective dose = 0.15 and 3.9 nM for motilin and GM611, respectively) but exhibited biphasic effects on spike activities superimposed on slow waves. With small depolarizations, the number of spike discharges increased, whereas larger depolarizations markedly reduced spike amplitude. Motilin-induced (or GM611-induced) depolarization appeared to be associated with the activation of monovalent cation-selective channels, and the reduction in the spike amplitude appeared mainly to be associated with inhibition of voltage-dependent Ca2+ channels. Furthermore, data from patch-clamp experiments suggested that Ca2+ release occurred from heparin-sensitive internal stores upon stimulation of motilin receptors by these agonists. Possible implications of these electrophysiological effects in motilin- or GM611-induced tonic and phasic contractions have been discussed.
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Abdullah NA, Hirata M, Matsumoto K, Aizawa H, Inoue R, Hamano S, Ikeda S, Xie Z, Hara N, Ito Y. Contraction and depolarization induced by fetal bovine serum in airway smooth muscle. THE AMERICAN JOURNAL OF PHYSIOLOGY 1994; 266:L528-35. [PMID: 8203546 DOI: 10.1152/ajplung.1994.266.5.l528] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We investigated the effects of fetal bovine serum (FBS) on the resting membrane potential and muscle tone of canine airway smooth muscles using tension recording and microelectrode methods. At concentrations > 0.1%, FBS induced a sustained increase in muscle tone. At concentrations > 1%, FBS depolarized the resting membrane potential of dog trachea in a dose-dependent manner. When FBS was dialyzed, it failed to induce a sustained increase in muscle tone or to depolarize the membrane, indicating that FBS contained factor(s) that induced contraction of dog airway smooth muscles. When FBS was dialyzed against distilled water, the outer solution which was freeze dried and then reconstituted (> 1% in original vol) induced a sustained increase in muscle tone, indicating that FBS contained dialyzable factor(s) that increased muscle tone and depolarized the resting membrane potential of dog airway smooth muscles. Methysergide (10(-6) M) or cyproheptadine (10(-6) M), nonspecific antagonists to serotonin receptors, 5-hydroxytryptamines (5-HT1 and 5-HT2), markedly reduced the FBS-induced increase in the muscle tone to approximately 20% of the original value but did not abolish the response. On the other hand, methysergide (10(-6) M) completely suppressed the increase in the muscle tone evoked by peak fractions obtained by application of the dialysate of FBS or 5-HT to a C18 reverse-phase column, indicating the peak fractions contained only 5-HT. These observations indicate that FBS contained 5-HT and an unknown factor(s) responsible for increase in the muscle tone of the airway smooth muscle induced by FBS.
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Abdullah NA, Assem ES. Ischaemia and mediator release: interrelationship in antigen-challenged sensitized guinea-pig kidney. AGENTS AND ACTIONS 1990; 30:106-9. [PMID: 1695424 DOI: 10.1007/bf01969011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Renal vasoconstriction and ischaemia that follow in vitro antigen challenge of isolated perfused kidney of sensitized guinea-pig appears to be a self-perpetuating process, starting with a primary peak of release of vasoconstrictor mediators and followed by secondary peaks (particularly of arachidonic acid metabolites) which are probably initiated by ischaemia/reperfusion damage.
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Abdullah NA, Torres BA, Basu M, Johnson HM. Differential effects of epidermal growth factor, transforming growth factor-alpha, and vaccinia virus growth factor in the positive regulation of IFN-gamma production. THE JOURNAL OF IMMUNOLOGY 1989. [DOI: 10.4049/jimmunol.143.1.113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
We have recently shown that epidermal growth factor (EGF) is capable of positive regulation of IFN-gamma production, thus establishing a functional relationship between nonhemopoietic growth factors and the immune system. In order to study this relationship further, EGF and the EGF-related growth factors transforming growth factor-alpha (TGF-alpha) and vaccinia virus growth factor (VGF), which stimulate cellular proliferation via binding to the EGF receptor, were studied for their functional and physicochemical effects on IFN-gamma production. In contrast to the positive signal of purified murine EGF and recombinant human EGF (both at 1 nM), neither synthetic TGF alpha nor recombinant VGF were capable of restoring competence for IFN-gamma production by Th cell-depleted spleen cell cultures. TGF-alpha and VGF, in molar excess, also failed to block the helper signal of EGF for IFN-gamma production. Thus TGF-alpha and VGF failed to functionally compete for the EGF receptor in the murine spleen cell system. Both TGF-alpha and VGF stimulated murine 3T3 cell proliferation at concentrations similar to those of EGF, and thus their failure to provide help for IFN-gamma production was not due to a general lack of biologic activity. Binding studies with 125I-EGF suggest that the EGF receptor on murine lymphocytes is not constitutively expressed, but inducible by the T cell mitogen staphylococcal enterotoxin A. TGF-alpha did not compete with 125I-EGF for the induced receptor. The data suggest that lymphocytes express a novel inducible EGF receptor that differs from that expressed on cells such as 3T3 fibroblasts.
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